Fabrication of PMMA Membranes with Nano-Pillars Array Using Template/Spin-Coating Method

Abstract

Template/spin-coating method was presented for fabricating single-layer nano-pillar array polymethylmethacrylate (SL-PMMA) and double-layer nano-pillar array polymethylmethacrylate (DL-PMMA) membranes. The different mass ratio of PMMA/DiMethyl Formamide (DMF) solution was dripped on single-layer porous anodic alumina (SL-PAA) or double-layer porous anodic alumina (DL-PAA) membrane and spun at 4000rpm speed for 30 seconds. The SL-PAA and DL-PAA membranes had been put into vacuum oven at 150°C for 2 hours, before SL-PMMA and DL-PMMA were removed. Experimental results show that the regularity degree of PAA fabricated in OAS/PAS is higher than that of PAA fabricated in PAS by two-step anodization method. The ordered pores and clear double-layer outline can be observed from the surface and cross-section FESEM images of DL-PAA membranes. When the content of PMMA in mixture solution is 20 wt%, the top shape of nano-pillars is convex, because the solution was completely filled in the pore of SL-PAA, and the length of nano-pillars is equal to the height of pore of PAA. However, the top pore amount on nano-pillars at ascending speed 20°C per minute is more than that of at ascending speed 10°C per minute. The PMMA membranes with ordered mid-hollow and porous nano-pillars will have wide application prospect in biosensors, chemical sensors, microcapsules fabrication fields due to many advantages such as simple operation, low cost, high specific surface area, etc.